In the related art, there is a known medical manipulator that is equipped with an elongated insertion section insertable into a body and that is used for treating the inside of the body by remotely manipulating a surgical tool installed in the insertion section (for example, see Patent Literature 1). The insertion section of such a manipulator is provided with a bendable portion for changing the orientation of a distal end surface equipped with, for example, a camera and the surgical tool.
Furthermore, in order to accurately control the bending angle of the bendable portion, a decelerating mechanism is used in a bending mechanism for bending the bendable portion. Specifically, with this configuration, large rotational motion of a shaft generated at the proximal end of the insertion section is converted into small linear motion by a threaded shaft that rotates together with the shaft and by a nut engaged with the threaded shaft. By utilizing this linear motion, wires connected to the distal end of the insertion section are pushed and pulled, thereby bending the bendable portion.